CHEVY NO POWER

1996 Chevrolet S-10

Electrical problem
1996 Chevy S-10 6 cyl Four Wheel Drive Manual

While driving down the interstate, all the power cut out. The radio turned off, the lights all turned off, the engine wasn't working, and then a couple of seconds later everything came back on. All the idiot lights on the dash came back on and the cd player picked up right where it left off. The engine had a code before it shut off and then when it " restarted" the code was gone. Later that night. Driving about 40mph downhill the truck lost power again. But this time didnt come back on again. I have checked the battery, the alternator is new, the connection to the starter and the fuse block are good. So I am just wondering what this could be. There is NO power. No lights in the cab, no engine start, no annoying key dinging when the door is open. Nothing.